Next thing to figure out would be how to handle the shared code and configuration. What i had in mind was that the wallet would have the node as a subtree, likewise the GUI with the wallet. There is some common code that could be mostly split (src/crypto) but other (src/util, src/common, …) will have to either be duplicate or become another interface between the projects.
Copying the configuration (the CI for instance) seems less concerning. Then the other big thing to figure out (which is a blind spot for me) is how we would organize the build system. cc @fanquake maybe you can clue me in.